Christophe Jacquet1, Auriane Marret2, Robin Myon2, Matthieu Ehlinger3, Nadia Bahlouli4, Adrian Wilson2, Kristian Kley5, Jean-Marie Rossi6, Sebastien Parratte2, Matthieu Ollivier7. 1. Institute of Movement and locomotion Department of Orthopedics and Traumatology, St Marguerite Hospital, 270 Boulevard Sainte Marguerite, BP 29 13274 Marseille, France; Aix Marseille Univ, APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Orthopedics and Traumatology, Marseille, France. 2. Aix Marseille Univ, APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Orthopedics and Traumatology, Marseille, France. 3. Service de Chirurgie Orthopédique et de Traumatologie, CHU Hautepierre, Hôpital de Hautepierre, Hôpitaux Universitaires de Strasbourg, 1 Avenue Molière, 67098 Strasbourg Cedex, France. 4. Laboratoire ICube, IUT de Haguenau 2 rue Boussingault, FR-67000 Strasbourg, France. 5. Institute of Movement and locomotion Department of Orthopedics and Traumatology, St Marguerite Hospital, 270 Boulevard Sainte Marguerite, BP 29 13274 Marseille, France. 6. Institute of Movement and locomotion Department of Orthopedics and Traumatology, St Marguerite Hospital, 270 Boulevard Sainte Marguerite, BP 29 13274 Marseille, France; Aix Marseille Univ, APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Orthopedics and Traumatology, Marseille, France; Centrale Marseille, 13451 Marseille Cedex 20, France. 7. Institute of Movement and locomotion Department of Orthopedics and Traumatology, St Marguerite Hospital, 270 Boulevard Sainte Marguerite, BP 29 13274 Marseille, France; Aix Marseille Univ, APHM, CNRS, ISM, Sainte-Marguerite Hospital, Institute for Locomotion, Department of Orthopedics and Traumatology, Marseille, France. Electronic address: matthieu.ollivier@ap-hm.fr.
Abstract
BACKGROUNDS: Despite the use of a locking plate a 30% incidence of lateral hinge fracture after Open-Wedge High Tibial Ostetomy was described in the literature. A finite element model was used to analyze if the presence of a hinge-securing screw in the osteotomy area, using Patient Specific Cutting Guides with a locking plate, decreases the stresses within the lateral hinge during compression and torsion. METHODS: A 3D model of a tibial sawbone was used to simulate an opening wedge of 10°. To apply loads on the tibial plateau, two supports were modelled on each tibial plateau to simulate the femoral condyles forces. A two second model with a hinge-stabilizing was defined with two different screws (diameter 2 mm and 4 mm). Two cases of static charges were considered 1) compression test (2500 N) 2) Torsion test (along the tibial mechanical axis). FINDINGS: During compression simulation, 17% of the total surface of lateral hinge was stressed between 41-50Mpa without hinge-securing screw while the amount of surface under stress between 41 and 50 MPa dropped significantly under screw stabilization (1% for the 2 mm and 3% for the 4 mm). During torsion stress simulation a decrease of the value of the maximal stress in the lateral hinge was also observed with the addition of a hinge-securing screw (37 MPa without screw, 27Mpa with a 2 mm screw and 25 Mpa with a 4 mm screw). INTERPRETATION: Positioning a screw intersecting the cutting plane at the theoretical lateral hinge location associated with a locking plate reduces lateral hinge stress in both compression and torsion. Those findings need to be confirmed by further specimens' mechanical testing.
BACKGROUNDS: Despite the use of a locking plate a 30% incidence of lateral hinge fracture after Open-Wedge High Tibial Ostetomy was described in the literature. A finite element model was used to analyze if the presence of a hinge-securing screw in the osteotomy area, using Patient Specific Cutting Guides with a locking plate, decreases the stresses within the lateral hinge during compression and torsion. METHODS: A 3D model of a tibial sawbone was used to simulate an opening wedge of 10°. To apply loads on the tibial plateau, two supports were modelled on each tibial plateau to simulate the femoral condyles forces. A two second model with a hinge-stabilizing was defined with two different screws (diameter 2 mm and 4 mm). Two cases of static charges were considered 1) compression test (2500 N) 2) Torsion test (along the tibial mechanical axis). FINDINGS: During compression simulation, 17% of the total surface of lateral hinge was stressed between 41-50Mpa without hinge-securing screw while the amount of surface under stress between 41 and 50 MPa dropped significantly under screw stabilization (1% for the 2 mm and 3% for the 4 mm). During torsion stress simulation a decrease of the value of the maximal stress in the lateral hinge was also observed with the addition of a hinge-securing screw (37 MPa without screw, 27Mpa with a 2 mm screw and 25 Mpa with a 4 mm screw). INTERPRETATION: Positioning a screw intersecting the cutting plane at the theoretical lateral hinge location associated with a locking plate reduces lateral hinge stress in both compression and torsion. Those findings need to be confirmed by further specimens' mechanical testing.
Authors: Raghbir S Khakha; Hamid Rahmatullah Bin Abd Razak; Kristian Kley; Ronald van Heerwaarden; Adrian J Wilson Journal: J Clin Orthop Trauma Date: 2021-10-01